This invention relates generally to the field of telecommunication systems and more specifically to a method and system for distributing a synchronization signal in a telecommunications network.
Conventional methods for distributing a synchronization signal utilize multiple levels of processors to direct the synchronization signal through the network. These methods also distribute the synchronization signal separately from control signals. Multiple levels of processors and distribution of the synchronization signal separate from other control signals, however, require complicated hardware and software in system modules for implementation, in addition to a relatively large number of lines for providing the separate signals, which results in lower efficiency and higher cost.
In accordance with the present invention, a method and system for distributing a synchronization signal in a telecommunications network are provided that substantially eliminate or reduce the disadvantages and problems associated with previously developed systems and methods. In particular, a composite synchronization signal is provided that includes timing and control messages, allowing reduced complexity in system modules and decreasing the number of lines needed for implementation.
According to one embodiment of the present invention, a system for distributing a synchronization signal in a telecommunications network is provided that includes a timing generator, a lower level distribution module, a bus control module and a plurality of cards. The timing generator is operable to provide a synchronization signal comprising timing and control signals. The lower level distribution module is coupled to the timing generator. The lower level distribution module is operable to receive and distribute the synchronization signal. The bus control module is coupled to the lower level distribution module. The bus control module is operable to receive and distribute the synchronization signal. The plurality of cards are coupled to the bus control module. Each card is operable to receive the synchronization signal and to synchronize based on the timing signals.
Technical advantages of the present invention include providing an improved system for distributing a synchronization signal in a telecommunications network. In particular, a timing generator provides a composite synchronization signal that includes timing and control messages. As a result, system modules may be designed without the complicated hardware and/or software required to generate the signals included in the synchronization signal. Accordingly, implementation costs are reduced, while efficiency is increased. In addition, including a plurality of messages in the composite signal allows the number of lines required for implementing the system to be reduced.
Other technical advantages of the present invention include providing additional levels of error detection. In particular, each bit other than the bits making up a synchronization word is repeated twice, and each message is repeated three times. As a result, the reliability of the synchronization word is improved, and frames containing errors are easily identifiable.
Yet another technical advantage of the present invention includes the generation of shelf identifiers. A module in each level of the system provides a portion of a shelf identifier for each shelf downstream of that module. As a result, a message within the synchronization signal may be provided for a specific shelf without requiring an address for the shelf. Instead, the shelf receives an identifier from an upstream module which may be used to extract the appropriate message for that shelf from the synchronization signal. Accordingly, shelf-specific messages for many shelves may be included with the other timing and control signals in a single synchronization signal.
Other technical advantages will be readily apparent to one skilled in the art from the following figures, descriptions, and claims.